Pulsation dampener



March 6, 1945. s. KAHN 2,370,965

PULSATION DAMPENER Filed July 16, 1943 Patented Mar. 6, 1945 UNITED; STATES o'FFicE A 2,370,965 y I r 1* .PULSATION DAMPENER 4 Samuel Kah'n," Bridgeport;""Coiin;, assignor' t Manning; Maxwell & Muo're, incomprated; Ne'w'w York, N. Y..-'a'c'orporationoI-NwJersey I Application July is; 1943,senamaasaoci 9 01mm: Cl. 1'38+;46-)

This invention-pertains to apparatus useful 'for indicating the pressure of fra fluid, andrelates more particularly "to a pulsation dampener or shock absorber-designed tob'e interposed between a source of pressure and 'anindicating or recording instrument. v

When a pressure gauge or similar sensitive instrument V is "used in association with apparatus wherein: fluid pressure pulsates :or fluctuates rapidlywithin the working range, forinstance when: a gauge is directly connected to the deliv'ery pipe ofa reciprocating pump, it is customaryto inter-- pose between the-pipe and gauge a flow restricting element, shock absorber or pulsation damps ener operative to damp'out rapid variations inpressure while \permitting relatively slow changes to afiecttheinstrument in usual manner, thereby minimizing flutter of -the instrument pointer and preventing damage to the delicate parts.

Fluids :of widely differing-viscosity- ;and havingworking pressure-'ranges' which vary .very greatly are encountered :in the engineering field =butpulsation dampencrs, as heretofore constructed,-havebeen .quite limited as "respects the viscosity .of fluid with which they may be used and the ipressure rangeto which they maybe-accommodated.

A principal object of the presentinvention-is to, provide a pulsation dampener which iscapable of effective use with fluids of different :viscosities andwhich may Ice-accommodated toa wide range of pressures. A further object of the invention is to provide a pulsation dampenerwof a broadrange of utility .but which :is :of simple,- durable, reliable and relatively inexpensive"construction; which occupies :but'little space, and which is applicable to instrumentsfor example pressure gauges, without necessitating 'anyrmodification .of the instrument itself. A :turther object is to provide' a pulsation dampener" which is vseli-clearing so that itis not readily clogged and made inefiectime by dirt or 'solid particles in the pressure'fluid. A- fur'ther object isto provides. pulsation "dampener as a single, r'self-icontained lunitlcomprisingl but "few parts and whichis very readily adiust able :for "use under widely diflerent conditions.- Other and further obi ects andadvantages of the invention will .be -pointed out in the' following more detaileddescriptionand by reference to the accompanying drawingwherein,

Fig. 1 is a diametrical se'ction ora pulsation strumentzhaving .aisupporting-stem or nipple ex dampener embodying the present inventiom'suchdampener bein'g shown associatedwith a pressure gauge, 'the latter being-'indicatedr-in'zbroken zlines and in part only; c

Fig. 2 is a ifragmentam section on :the same plane =asi Fi'ga-tl, :omitting certain of the :parts;

Fig. 3 -:a wiew similar to: Fig. :2 showing the passage-constricting rpm in: partially raised position;

Fig. 41s a plan view,,-- tolarger scale, -of,a cylindricail block -or:bu'shing forming la part of the pulsation dampening means;

- Fig. 57 is a jPIBIILViEW 'OfEBl cover member or seal ing-disk-fom1ing-part oftheapparatus;

.Fig-;. 8 is a section -onthe-line -8--8 of- Fig; i7

Figr-Q is a planyiew ef ra pressure-applying nut I formin's partiof the apparatus; and- Fig; 10 is a section onthe line l0-.-'-l 0 of :Fig. 19.

I Referring to theidraw-ing, the numeralzl designates generally the pulsation-dampening device of the rpresentzinvention, such device beingshown associated with a pressure gauge 2 or similar internally :screw threaded in-iusual manner.

The pulsation dampener-comprises a substantially cylindrical casing 3 of any-suitablematerial,--for vex-ample metal or a :moulded plastic,

having an externally screw-threaded :lowerend err-nipple portion 4 m "connection-iota supply pipe P.: This nipple portion lis provided with an axial bore 5 which :opensat its .upper end intoa vertically ielongatescylindrical chamber in the body-:of-thecasing. The upper-rportion-of-the inner :wall -of-this chamber :is screw threaded asshownat i. The door of this chamber has anannular marginal shoulder ,1 bounding a shallow downward extension '8 ofthechamber into which the passage-iepensw A cylindrical block or bushing 9 (Figs. 1, =4,- 5 and 16,) having fiat upperand'lower surfaces is disposed within the chamber. in the body-portion of "the casing-and :rests upon the annular ishoulder: 1. This bushing isiprovided with a plurality ofparallel, axially extending lpassages ll, 10,

10 .etc.,= -of= {progressively 2 different diameters,

these'-- passages extending through -the 'bushingfromitop to bottom and all opening at their lower: ends into the space- 8. Attheir upper ends the several passagesvarefurnishedwith;coaxial coun terbores I I extending down-i-from the upper end l3-offl;h e1bushing, :the several counterbores being.

of 1 the same diameter; T r

The upper surface' ofthe bushing a is 'substan; tially'flat and upon zth'iscflat surfacerestsiacover member orsealingidisk:M -(Figs: 7 and-8):; This 68 cover memberor disk ds of substantial thickness,

having a hat bottom surface I6 from which projects a short tubular boss I5 of such external dimensions and so located that it may seat in any The axes of the sev- 1 one of the counterbores I I. eral passages I0, I I0 etc., are spaced equally in a radial direction from the axis of the bushing l 9 and the boss I5 of the cover I4 is so arranged I eter of the largest of the passages l0, [0, etc.,

and at its upper end opens into a counterbore I8. 3

To assist in selecting the desired passage in the bushing Q, the circumferential outer surface of 1 the latter is preferably provided with index charis sci ewed down so as to compress the cover and thus seal the upper ends of all of the passages In, Ill etc., in the bushing 9 except the passage in which the pin is disposed. The gauge stem is then screwed into the upper part of the chamber "the cover is at least as large as the largest of the passages in the bushing 9 while the counter- I bore. l8 is'of substantially greater diameter. .If the pin be lifted by the pulsation of the fluid, the

: head of the pin will ultimately engage the slopacters I2, for example numerals, disposed radially v with respect to the axes of the several passages. An annular nut I9 (Figs. 1, 9 and 10) provided with external screw threads which are engageablewith the internal screw threads 6, has a lower, annular flat surface which is designed to.

engage the cover I4 and thusclamp the cover edge of surface 20 and is always in free communication with the counterbore I8 regardless of the position in which the cover may be placed.v

The upper wall of the cavity 2| slopes inwardly and upwardly as shown at 22, the cavity mer ing with an axial bore 23 of substantial diame eter,'opening into the upper part of the chamber of the casing 3. -The nut I9 is preferably provided with a transverse slot 21 for the application of a suitable wrenchor other tool whereby thenut maybe screwed downwardly and into forcible engagement with the cover I4, thus press- 40 ing the cover leak-tight against the upper flat surface I3 of the bushingjand at the same time pressing the lower surface of the bushing into leak-tight contact with the shoulder I.

The pulsation dampener comprises a pin 25 of a diameter somewhat less than the diameter of the smallest of the passages ID, W etc. When this pin is disposed in any one of the passages'it constricts such passage, although still leaving some space between it and the wall of the passage through which pressure fluid may pass. The pin is preferably of a length such that when its lower end rests upon the bottom of the chamber 8 (Fig. 1) its upper end is disposed in the counterbore I8 of the cover I4. Preferably this pin is provided with a head 26 at its upper end to facilitate its withdrawal from the passage when" desired By the employment of passages Ill, Ifl etc., of

different diameters it becomes possible, by dise posing the pin 25 in the properly selected passage; to accommodate the pulsation dampener for use u with fluids of-diiferent viscosities or which are subject to different rates 'of .pressure fluctuation or to different ranges of pressure. In thus adapting the instrument for use under any particular conditions, the nut I9 is first removed, the

pin 25 is withdrawn from the passage in which: it was previously disposed, the cover I4 is lifted and rotated until its single aperture I1 is aligned with the selected passages Ill, Ill etc., the boss I5 of the cover is seated in the corresponding counterbore II, the pin is then dropped down through the counterbore I8 and aperture ll and intothc' 7 5 selected'passage in the bushing 9'," andthe nut I9 rise.

ing surface 22 0f the cavity 2|, thus limiting its The diameter or the head 26 of the pin is such that it exerts no appreciable restrictin effect upon the passage of fluid through the counterbore I8. In response to pressur pulsati-on, the pin'rises and falls, thus preventing the vary narrow annular canal between it and. the wall of the passage frombecoming plugged with sediment. The head 26 of the pin is not necessary to affect such motion, but is useful in lifting' the pin when it is to be transferred to a different passage.

The device as thus provided is of small external dimensions and comprises but a single moving part, to wit, the pin 25. The casing of the device may be connected directly to the supply pipe in the same way that the gauge nipple is usually connected, and the gauge nipple is merely screwed into the upper part of the casing so that no special or unusual fittings are required. Furthermore as above described, it is a very simple operation toadapt'this pulsation dampener for use under different conditions and in doing so no substitution of parts is necessary, the only requirement being that the pin 25 be shifted from one passage to another. i

While one desirable embodiment of the invention has herein been described by way of example, it is to be understood that the inventionis broadly inclusive of any and all modifications and substitutions which fall within the terms of the appended claims. I

Iclaim: 7 1. A self-clearing pulsation dampener for use with pressure gauges, said pulsation dampener comprising a part having therein a plurality of passages respectively of difierent transverse section. a movable passage-constricting element constructed and. arranged to cooperate at will with *any selected one of said passages thereby to restrict the flow capacity of said selected passage, andmeans operative completely to close'all .of the several passages except that'with which. the constricting element for the time beingcooperates.'-

, 2. A self-clearing pulsation dampener for use with pressure gauges, said pulsation dampener comprising a 'part having therein. a plurality of parallel passages respectively of diiferent diameters, a passage constricting element constructed and arranged to cooperate-with any selected one of said passages thereby .to restrict thexiiow cablocks, all 0f.,the.passages except that one with. which the constricting'.element for the time being cooperates.

esteem 'closure member operative completely to close all of the passages except that within which the pin is disposed.

4. A pulsation dampener for use with pressure gauges, said pulsation dampener comprising a part having therein a plurality of parallel passages respectively of difierent diameters, each passage, at its upper end, having a counterbore, all of said counterbores being of the same diameter, a closure member having at its under side an annular boss designed to fit in any selected one of said counterbores, said closure member, when its boss is so seated in a selected one of said counterbores, completely closing the other counterbores, and a passage-constricting pin extending through the annular boss in the closure member and into the corresponding passage, said pin being or such diameter that it may be disposed with a loose fit in any selected one of the passages thereby to restrict fluid flow through the selected passage.

5. A pulsation dampener comprising a case provided with means for connecting it to a supply pipe and to a pressure gauge respectively, said casing having therein an elongated chamber, a block housed in the lower part of said chamber, said block having therein a plurality of parallel passages respectively of different diameters all communicating at their lower ends with the supply pipe, a cover member engaging the upper surface of the block, said cover member having a single aperture which may be arranged coaxially with any selected one of the passages, the cover being designed completely to close all but the selected passage, a movable passage-constricting and clearing pin operative to restrict any of said passages in which it may be disposed, said pin projecting through the aperture in the cover member, and means for pressing the cover leak-tight against the upper surface of the block.

6. A pulsation dampener comprising a'casing having provision for connecting its lower end to a supply pipe and its upper end to a gauge stem, said casing having therein a cylindrical chamber having an annular shoulder at its lower end, the space bounded by the shoulder communicating with a passage designed to lead to a supply pipe, a cylindrical bushing seated on said shoulder within the chamber, the bushing having a plurality of axially extending passages respectively of different diameters and spaced apart circumferentially of the bushing and at equal distances from the axis of the bushing, each said passage having a counterbore at its upper end, the several counterbores being of equal diameter, a cover disk having an annular boss projecting from its under surface, said boss being designed to fit into the counterbore of any selected passage in the bushing, a flow-restricting pin passing loosely through the annular boss of the cover,

the pin being of such diameter as to fit loosely in any selected one of the passages in the bushing, and a cover-clamping nut having threaded e imeo ar through the, selec ed: pas a e 3s uea ementiwlthz srtionrpir elch m err,s id'icov rec am ineunuti in sdesis edi oenress; he b shin a-lealseti htl a ainst. the; annul tz houlder and rat; th same: the-louver" 1e. 'klishtiaeain tr glie -i u i cel ir heabush ns and hayin le ate-1. tyr n-its.i nderxsurface ar an edetp erndti;lime; ted upwardt ovemen eo tthezp i 7.! Awpulsamon erial-comprisin gassing, mznavin s n z ri'sion-l. r-rce ne tin its lowen ndl a supply pipe and its upper end to a gauge stem, said casing having therein a cylindrical chamber having an annular shoulder at its lower end, the space bounded by the shoulder communicating with a passage designed to lead to the supply pipe, a'cylindrical bushing seated on said shoulder within the chamber, the bushing having a plurality of axially extending passages re-' spectively of diflerent diameters and spaced apart circumferentially of thebushing and at equal distances from the axis of the bushing, a cover disk having a single aperture therein so located that it may be aligned with any selected one of the passages in the bushing, a flow-restricting pin designed to pass through the aperture in the cover and to be disposed in any selected one of the passages with which the aperture in the cover may be aligned, the pin being of a diameter such that it fits loosely in the 5 aperture in the cover and in any passage in which it may be disposed, and a cover-clamping element operative to press the bushing into leak- ,tight contact with the annular shoulder and at the same time to clamp the cover leak-tight" against the upper surface of the bushing thereby to close all of the passages except that which contains the pin. l

8. A pulsation dampener comprising a casing having provision for connecting its lower end to a supply pipe and its upper end to gauge stem, said casing having therein a cylindrical chamber having an annular shoulder at its lower end, the space bounded by the shoulder communicating with a passage designed to lead to the supply pipe, a cylindrical block seated on said shoulder within the chamber, the block having a plurality of axially extending passages respectively of different diameters'and spaced apart circumferentially of the block and at equal distances from the axis of the block, a cover disk having a single guide aperture whichmay be placed in alignment with any selected one of the passages in the block, the cover completely closing all of the other passages, a flow-restricting pin fitting loosely in the guide aperture in the cover, the

pin being of such length that when its lower end rests upon the bottom of the chamber in the easing its upper end is above the block, the pin having a head at its upper end and the cover having a counterbore for the reception of the head of the pin, and an annular nut having threaded engagement with an internally threaded upper portion oi the chamber, said nut being operative to clamp the cover leak-tight against the upper surface of the block, the nut having a cavity in its under surface thereby to permit the head of the pin to rise above the cover, the nut also having a stop member to limit such rise of the pin. I r

9. A pulsation dampener having a casing provided at its lower end with means for connecting it to a supply pipe and means at its upper end for connecting it'to a gauge, the casing having a chamber therein open at the top of the casing and a bore of substantially smaller diam inter ally amended-mom,

eter than that of the chamber leading from said chamber to the lower end of the casing, the chamber having a floor, and flow-controllin means within the chamber, 'said flow-control means comprising a part having therein a passage so located that its axis intersects the chamber floor, the parts being so constructed and ar-'- that the passage communicates at its ranged lower end withsaid bore,- a flow constricting pin fitting loosely in said passage,-the pin having a head at its upper end and being of such length that when its lower end restson the floor of the chamber its head is above the upper endof the passage, and an element operative by engagement with said head to limit rise of the pin,'said limiting element being so constructed and arranged that it does not restrict the flow of fluid through the passage whatever the position of the pin.

' SAMUEL 

